My 3.5yr old enjoyed this for about an hour, then was ready for the next app up. It only allows addition to the amounts of 2,3,4, or 5. My son would have been much happier with this app had it allowed addition to the number 10. The lower numbers got boring too fast and there is no variation in the game -- youre always feeding that little guppy.
If your child is already using some of the popular preschool math apps (think monkey, park) then this is way basic. Excellent for a 36 month old, not much beyond. However, if your child is struggling with the concepts of basic addition in the 3-5 yr range,then this might be a good remedial tool. This app doesnt "learn" from your childs struggles or successes, you have to change the levels manually, I.e. it will have your child practice adding 2 or 3 forever until you go to the menu and manually tell it to start giving your child 4 or 5 to add. "Prizes" are just selecting a temp coloring for your fish -- not that rewarding. Not worth a premium price.